From U.S. Pat. No. 4,265,439 a technique for the manufacture of a hose package of the abovementioned type is known which starts out from a hose of flexible material, e.g. plastic film. This U.S. patent specification discloses the provision of lower folding means, upper folding means and fixing means, the fixing means being adapted so as to be moved from an initial position to a fixing position wherein the fixing means in order to form a first wall element of the hose package, fixes a predetermined length of an end portion of the hose against the lower folding means. The upper folding means subsequently is moved from an initial position to a position close to the lower folding means and opposite the side of the lower folding means where the wall element formed first is situated. During this movement the upper folding means pulls with it a portion of the hose and thereby forms two further wall elements of the hose package. The lower folding means thereafter is moved from the position wherein the two wall elements just mentioned were formed, and thereafter to a position on the opposite side of said two wall elements, whereupon the upper folding means returns to its initial position. The lower folding means then is moved back to the position wherein the fixing means fixes the pulled-down hose against the lower folding means. During this movement the lower folding means leads the two wall elements just formed to positions adjoining the wall element(s) formed earlier. The means specified repeat thereafter the movements just described, and in each such cycle of movements form two new wall elements. The process is repeated until a predetermined number of wall elements has been obtained and the desired hose package has been manufactured.
The abovementioned patent specification discloses an apparatus whose folding means form polygons. The design of the upper folding means is not described in detail, but it is evident from the figures that it is constituted of a number of plates which are connected in the outer corner regions of the upper folding means because the plates are bent in those regions. The lower folding means also consists of plates, which each have end regions included in two unequal corner regions of the lower folding means corresponding to two unequal corner regions of the upper folding means. In the corner regions the plates of the lower folding means are terminated by substantially vertical edges. Between the end regions of the lower folding means situated adjoining one another an opening is provided whose size is altered during the folding process. In accordance with said U.S. patent specification, the upper folding means, when pulling down the hose for the formation of new wall elements, passes inside the lower folding means, that is to say closer to the center in relation to wall elements of the hose package already formed. To make this passage possible, the lower folding means, by moving apart the end regions adjoining one another, moves the wall elements of the hose package formed already to such positions that the upper folding means becomes clear of the wall elements, even in the parts of the corner regions formed where the lower folding means is not in contact with the last formed wall element. To ensure a satisfactory function it is necessary, therefore, that the upper folding means in its bent corner region should be at a relatively great distance from a connecting plane between the end edges of the lower folding means in the corresponding corner region. This in turn leads to an undesirably great distance between the newly added folds and the folds completed already, which complicates the folding process in the corner regions of the hose package. Also, the return of the lower folding means to the initial position, and in that case especially its movement inside the wall elements formed already, is critical in accordance with the known technique, since the space inside the wall elements formed already is limited in the corner regions. The wall elements formed already have a tendency, therefore, to accompany the folding means, at least in the upwards directed movement. Such an undesirable pulling along of a wall element as a rule causes damage to the wall element, e.g. the formation of holes in the material.
A further problem which arises in connection with the design of the folding means as described above is that the formation of wrinkles is readily possible, and that undesirable braking of the film may occur in the corner regions when the upper folding means pulls the hose down for the formation of further wall elements. Wrinkle formations and braking effects bring with them only too often damage to the material and, in unfortunate cases, penetration of the material so that holes are formed. Damage to the film of the aforementioned kind are difficult to detect on the finished hose package and are not acceptable.
Corresponding problems arise also in the embodiment where the hose package is formed in that newly added folds are being placed outside the folds formed already.